[c-nsp] L2TP tunnel for BGP peering

Joe Maimon jmaimon at ttec.com
Sun Jun 18 21:52:14 EDT 2006


Why would you do L2TP and not GRE?

If you have enough IP routing to put up a working l2tp tunnel, then you 
have enough to do multihop ebgp.

If your ip routing and your desired BGP peering is running over a 
different provider, then a tunnel could be neccessary to avoid routing 
loops.

The only gain you could possibly have with this setup is if Provider A 
(the route to provider B) is cheap/fast/reliable to get to B but nowhere 
else, and provider B is cheap/fast/reliable to get everywhere else.

Otherwise, if you are connected to your new provider, tunneling shouldnt 
even enter the picture.

Now as an aside, if you are a network engineer that is getting stumped 
by technical crap spewed from management, something is very wrong.

Either you dont know you business or your management cant mind theirs.

Kanagaraj Krishna wrote:

> Its one option suggested by my management for our next upstream provider (@
> getting bandwidth).  I need to understand the pros and cons of the running
> BGP on a L2TP tunnel like overhead, link quality etc, before moving any
> further. I found stuff on L2TP but not related to BGP. Hope to get more
> inputs. Thanks.
> 
> Regards,
> Kana
> 
> ----- Original Message -----
> From: "Robert E.Seastrom" <rs at seastrom.com>
> To: "Kanagaraj Krishna" <kanagaraj at aims.com.my>
> Cc: <cisco-nsp at puck.nether.net>
> Sent: Wednesday, June 14, 2006 7:04 AM
> Subject: Re: [c-nsp] L2TP tunnel for BGP peering
> 
> 
> 
>>Kanagaraj Krishna <kanagaraj at aims.com.my> writes:
>>
>>
>>>Hi,
>>>    Due to cost issues tied to direct IPLC, we are thinking of running
>>
>>you mean international private leased circuits?
>>
>>
>>>BGP sessions with upstream providers through L2TP tunnels. It would be
>>>very helpful,  if anyone in the group share advises on the pros and
>>>cons of this setup. A few other doubts are:
>>
>>this sounds dodgy to me and like a bad plan, but read on...
>>
>>
>>>- We have concerns on the stability of the virtual link like quality
>>>drop etc. Are there any mechanism to improve this as drop of  tunnel
>>>would cause BGP flapping/dampening ?
>>>- What would be the overhead on the bandwidth throughtput?
>>
>>what problem exactly are you trying to solve here?  you have to get
>>bandwidth from somewhere...  is the problem that you can't get frame
>>relay or other appropriate technology via vsat or terrestrial circuit
>>at a reasonable price?
>>
>>                                        ---rob
>>
>>
>>>
>>>We would like to get more input before looking into further. Thanks
>>>
>>>
>>>Regards,
>>>Kanagaraj Krishna
>>>
>>>
>>>_______________________________________________
>>>cisco-nsp mailing list  cisco-nsp at puck.nether.net
>>>https://puck.nether.net/mailman/listinfo/cisco-nsp
>>>archive at http://puck.nether.net/pipermail/cisco-nsp/
>>
> 
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